48 CIECULAE 16 8, U. S. DEPARTMENT OP AGBICITLTTTEE 



are laid upon the young tender leaves in the field. The young larvae 

 feed first upon the epidermis of the underside of the leaf, but very 

 soon they bore into the stem. Pupation takes place within the stem 

 below the soil surface, differing in this respect from Chilo simplex. 



Shiraki (170) has published a detailed account of the life history 

 and habits of the species in Taiwan, in which island it is a pest of 

 rice only. From four to six generations are produced each year. 

 There the damage amounts at times to 10 per cent of the crop, as 

 compared with the usual damage of about 20 per cent in the Fukuoka 

 and Saga Prefectures in Kyushu, these being the worst infested sec- 

 tions in Japan proper. In Taiwan as many as 50 per cent of the 

 eggs may be parasitized by Triohogrumma jmpanica Ashm.. 15 per 

 cent by Ceraphron heneftciens Zehnt., and 30 per cent by Tetrasti- 

 clius sp. The total parasitism of the larvae does not exceed 10 per 

 cent. Control measures recommended are the plowing and burning 

 of stubble, collection of adults by lantern traps and net, and the clip- 

 ping of the ends of the leaf blades at the time of transplanting, thus 

 removing the eggs. 



Considerable work has been done, particularly in Honshu, in the 

 distribution of the egg parasites of both Chilo simplex and Schoeno- 

 bius incertellus in an effort to increase the effectiveness of the various 

 native species. Ojima (HI) has devised an apparatus in which the 

 field-collected egg masses, instead of being destroyed as is the usual 

 practice, are inclosed in such a way that the emerging parasites can 

 readily escape, while the young caterpillars can not. The work along 

 this line to date has been confined to the liberation of the parasites 

 from the field-collected eggs of the current generation, rather than 

 to insectary rearings. The cumulative effect of this method may be 

 to increase the parasitism of the later host generations, but the effect 

 upon the first is relatively slight. 



Aglossa dimidiata (149) is distributed throughout all of the main 

 islands of Japan and extends from Chosen to Burma and India. In 

 Hokkaido there is one generation per year, and the adults are found 

 in the field during the latter part of July and August. The eggs are 

 laid upon the head or sheath of the rice and hatch in two weeks. 

 The caterpillars are recorded by Nishikawa as feeding at times upon 

 the eggs of the silkworm. It is primarily a pest of stored grain. 



Cnaphalocroeis mediiialis (96) is a very common though usually 

 not a serious pest upon rice in Japan, Chosen, Taiwan, and China. 

 It feeds also upon wheat and barley. In northern Japan there are 

 two or three broods each year, but in Taiwan six or seven are pro- 

 duced during the season. The eggs are laid in clusters upon the 

 foliage. Hibernation is in the mature larval stage. 



The pyralid Bradina admixtalis (95) at times becomes a serious 

 pest upon rice in Japan, particularly in Kyushu and western Honshu. 

 There are two broods each year, and the winter is passed in the 

 mature larval stage in the straw. The adults of the two generations 

 appear in May and from July to August, respectively. The eggs 

 are laid in rows of three or four upon the leaf and hatch in 10 days. 

 The larvae fold the leaves and feed upon the tissue of the underside 

 only. The pupa has a thin, paper-like cocoon, which is formed in 

 the rolled leaf. According to Murata (108) there are three genera- 

 tions each year in the southern sections, the adults appearing in 



